This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. DEVELOPMENT AND APPLICATIONS OF NEW PROBES AND METHODS FOR CORRELATED LIGHT AND ELECTRON MICROSCOPY, LIVE IMAGING, AND FUNCTIONAL ANALYSIS In this subproject, our efforts are directed at further improving and refining probes and methodologies to enable correlated light and electron microscopy. These include the highly successful tetracysteine tag/biarsenical labeling technology acknowledged to be a powerful and versatile method for correlated time-lapse light and electron microscopy, and miniSOG, a new genetically encodable fluorescent protein designed specifically for correlated light and high- sensitivity electron microscopic localization of proteins and macromolecular complexes. We are also continuing our efforts to develop additional new probes for correlated microscopies.